The industrial robot is a flexible and cheap standard component that can becombined with a milling head to complete low accuracy milling tasks. Thefuture goal for researchers and industry is to increase the milling accuracy, suchthat it can be introduced to more high value added operations.The serial build up of an industrial robot bring non-linear compliance andchallenges in vibration mitigation due to the member and reducer design. WithAdditive Manufacturing (AM), the traditional cast aluminum structure couldbe revised and, therefore, milling accuracy gain could be made possible due tostructural changes.This thesis proposes the structural changes that would improve the millingaccuracy for a specific trajectory. To quantify the improvement, first the robothad to be reverse engineered and a kinematic simulation model be built. Nextthe kinematic simulation process was automated such that multiple input parameterscould be varied and a screening conducted that proposed the mostprofitable change.It was found that a mass decrease in any member did not affect the millingaccuracy and a stiffness increase in the member of the second axis would increasethe milling accuracy the most, without changing the design concept. To changethe reducer in axis 1 would reduce the mean position error by 7.5 % and themean rotation error by 4.5 % approximately, but also reduces the maximumspeed of the robot. The best structural change would be to introduce twosupport bearings for axis two and three, which decreased the mean positioningerror and rotation error by approximately 8 % and 13 % respectively. / En industrirobot är en anpassningsbar och relativt billig standardkomponent.Den kan utrustas med ett fräshuvud för att genomföra fräsoperationer med låg noggrannhet. Det framtida målet för forskare och industri är att öka noggrannheten vid fräsning så att dess användningsområde kan utökas till ändamål som kräver högre precision.Den seriella uppbyggnaden av en industrirobot medför icke-linjär styvhet och därmed utmaningar vid vibrationsdämpning. Detta på grund av den strukturella uppbyggnaden då en industrirobot kan förenklat sägas vara uppbyggd av balkelement som i ledpunkterna kopplas samman av växellådor. Med friformsframställning kan en mer komplex struktur erhållas jämfört med traditionellt gjuten aluminiumkonstruktion därmed skulle en ökad noggrannhet vid fräsning kunna uppnås.Det här examensarbetet föreslår strukturella ändringar som skulle kunna öka noggrannheten vid fräsning för en specifik fräsbana. För att kvantifiera förbättringen, var det först nödvändigt att utgående från tillgänglig data konstruktion en specific robot samt att bygga en kinematisk modell. Därefter automatiserades beräkningsflödet så att ett flertal indata kunde varieras. Detta resulterande i en kombinationsstudie som visade den mest gynsamma strukturella förändringen.Det visade sig att en minskning av balkelementens massa inte påverkade nogrannheten. Att öka styvheten i balkelementet från den andra axeln skulle d¨aremot öka nogrannheten mest utan att behöva ändra robotens uppbyggnad.Att byta växellåda i första axeln kan öka positionsnogrannheten med nära 7.5 % och rotationsnoggrannheten med cirka 4.5 % men ändringen sänker samtidigt den maximala hastigheten. Den bästa strukturella förändringen vore att introducera ett stödlager vid axel två respektive tre, vilket skulle förbättra positionsnogrannheten med cirka 8 % och rotationsnogrannheten med nära 13 %.

This thesis deals with elasto-kinematic properties of multi-link rear suspension system, based on simulations. The creation of computational model and simulation of elastokinematics are based on specialized modules of the HyperWorks software. The thesis idea is to create new models and improve their properties. The chapter introduction presents and discusses the current knowledge state in the issue of elasto-kinematic characteristics of the vehicle suspension. Previously published works are presented in this section. The following section defines basic terms, features and design elements concerning the topic vehicle suspension and vehicle axle, which can help readers to orientate in this field. The first part of the thesis is focused on the collection of high-quality input data to create the MBS computational model based on the real suspension components. The determination of kinematic suspension points, experimental measurements of inertia moments of supporting elements of the suspension and measurements of deformation characteristics of rubber-metal bushings are presented in the thesis. There are also measuring characteristics of force elements such as springs or shock absorbers. Then the proposed method of measuring elasto-kinematic characteristics of the suspension using testing machine for model validation is also introduced. The second and main part is devoted to creating a new MBS simulation models of multi-link rear suspension using HyperWorks system. The suspension model is improved by successive steps, from kinematic model, through model with flexibility of the bushings, to the complex model in which the flexible properties of all supporting elements are reflected. The properties of the used models are described together with arising calculation problems. The results discuss the impact of elements flexibility and individual structural alternatives on elasto-kinematic characteristics of the suspension system.

Ride and handling are important areas for safety and improved vehicle control during driving. To meet the demands on ride and handling a number of measures can be taken. This master thesis work has focused on the early design phase. At the early phases of design, the level of details is low and the design freedom is big. By introducing a tool to support the early vehicle body design, the potential of finding more efficient structures increases. In this study, topology optimization of a vehicle front structure has been performed using OptiStruct by Altair Engineering. The objective has been to find the optimal topology of beams and rods to achieve high stiffness of the front structure for improved ride and handling. Based on topology optimization a proposal for a beam layout in the front structure area has been identified. A vital part of the project has been to describe how to use topology optimization as a tool in the design process. During the project different approaches has been studied to come from a large design space to a low weight architecture based on a beam-like structure. The different approaches will be described and our experience and recommendations will be presented. Also the general result of a topology-optimized architecture for vehicle body stiffness will be presented.